Support for topic settings deletion if they are present on the broker but not in config (with flag to enable)

[fpacifici]

Hi,
I really like the tool. thanks.

If I remove a topic setting from my config, while the setting is still on the broker, topicctl would not delete it and leave it as it is

Found 1 key(s) set in cluster but missing from config:
-------------------------+----------------
                     KEY | CLUSTER VALUE
-------------------------+----------------
  message.timestamp.type | LogAppendTime
-------------------------+----------------
These will be left as-is."

Topicctl though supports deletion of a setting by setting it to empty string.
https://github.com/segmentio/topicctl/blob/master/pkg/admin/brokerclient.go#L770-L774

Is there any reason to specifically avoid deleting topic settings when there is a mismatch between config and broker? I think that would make topic settings management actually declarative.
I can see the potential for damages (provide an empty config by mistake) when allowing this, though updates go through user confirmation and there could be a flag to enable the destructive behavior.

If there is any interest in having this feature I would try to build it.